An implantable medical lead typically includes a tubular-shaped main lead having one or more conductors or coils to sense or provide stimulative biologic, electrical signals, and a lead connector coupled to one end of the main lead. The lead connector is, in-turn, configured to electrically and mechanically plug into and couple to a header or connector bore of a pacemaker, implantable cardioverter defibrillator (“ICD”), or other type of pulse generator.
An IS4/DF4 lead connector is standardized lead connector having an injection molded, reaction injection molded (RIM) or potted, cylindrical body (typically of a thermoplastic, or thermoset material), the connector body having a proximal end configured to connect into a header of an active implantable device of some type, and a distal end configured to connect to the conductors/coils within the main lead. Such lead connectors have multiple electrical contacts in the form of contact rings which are spaced along and are flush with a surface of the connector body. Lead connectors may also include a pin contact extending from the proximal end. A conductor typically extends through the lead body from each contact ring and projects from the distal end of the molded body so as to provide a connection point for the conductors of the main lead. Similarly, a main body pin may extend along a central axis of the lead connector from the pin contact at the proximal end and also project from the distal end of the molded body.
Conventional practices for the manufacture of lead connectors include an injection molding process, or a reaction injection molding process, or liquid silicone molding process, or a potting process wherein the ring connectors, conductive pins, and the central pin/pin contact (if being employed) are arranged within a mold cavity. A thermoplastic material, or other suitable material, is then injected into the mold cavity to over-mold the conductive pins, ring connectors, and main body pin to form the cylindrical body of the lead connector.
Tight tolerances are required for the safe and effective performance of lead connectors, including IS4/DF4 connectors. However, the injection molding process presents many challenges and shortcomings that make maintenance of such tight tolerance difficult to meet and which can result in high production costs and low manufacturing yields.